Dynamic bus with singular central precharge
AssigneeInternational Business Machines Corporation
InventorsJeffrey S. Zimmerman, John A. Fifield, Christopher P. Miller, Robert E. Busch
Life of this patent
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Abstract
A dynamic bus system with a central precharge device is disclosed that utilizes a controller circuit with a one-shot generator and write synchronizing circuits in combination with logic output modules having pull-up/down devices. The issuance of the output enable (OE) signals is interlocked with the turn-off of the precharge. Thus, data is written to the dynamic bus only when the precharge device is inactive, avoiding bus collisions. The resulting circuitry not only ensures the precharging of the bus before the data write to the bus, but will allow the synchronized OE signals to be issued during the same clock phase as the precharge signal.
Claims11
A system for a controlled write to a dynamic bus, comprising:
- a) a writing device, coupled to said dynamic bus for writing data to said dynamic bus;
- b) a precharge device, coupled to said dynamic bus for precharging said dynamic bus;
- and
- c) a control device, coupled to a clock input that receives a clock pulse, said precharge device, an output enable input, and said writing device;
- said control device for controlling both writing data to said dynamic bus and precharging said dynamic bus, including:
- c1) a pulse generating device, coupled to said clock input for generating a first and a second pulse of equal duration wherein said second pulse is offset in time from said first pulse, and the duration of said first pulse and said second pulse is shorter than said clock pulse;
- c2) a first logic device, coupled between said pulse generating device and said precharge device for enabling said precharge device for a duration shorter than said first pulse duration;
- and
- c3) a second logic device, coupled to said pulse generating device, said output enable input, and said writing device, for enabling writing data to said dynamic bus only when the precharge device is inactive.
A method for synchronizing a controlled write to a dynamic bus with a precharging of the dynamic bus, comprising the steps of:
- a) inputting a clock pulse into a pulse generating device;
- b) generating with said pulse generating device a first pulse and a second pulse of equal duration from said clock pulse, wherein said second pulse is offset in time from said first pulse, and the duration of said first pulse and said second pulse is shorter than said clock pulse;
- c) generating a precharge pulse from said first pulse and said second pulse, wherein the duration of said precharge pulse is shorter than said first pulse;
- d) enabling a precharge device for said duration of said precharge pulse;
- e) generating a synchronized output enable signal from said first pulse and said second pulse;
- and
- f) enabling a writing device with said synchronized output enable signal for writing data on said dynamic bus only when said precharge device is inactive.
A system for a controlled write to a dynamic bus, comprising:
- a) a writing device, coupled to said dynamic bus for writing data to said dynamic bus;
- b) a precharge device, coupled to said dynamic bus for precharging said dynamic bus;
- and
- c) a control device having a first input coupled to a clock signal line and a second input coupled to an output enable signal line, and having a first output coupled to said precharge device and a second output coupled to said writing device;
- said control device including:
- c1) a first logic device, coupled between said clock input and said precharge device for enabling said precharge device for a duration shorter than said clock pulse;
- and
- c2) a second logic device, electrically interlocked with said first logic device and coupled to said writing device for enabling writing data to said dynamic bus immediately upon turn off of said precharge device.
A system for controlled write to a dynamic bus, comprising:
- a) a writing device, coupled to the dynamic bus for writing data to the dynamic bus for writing data to the dynamic bus;
- b) a precharge device, coupled to the dynamic bus for precharging the dynamic bus;
- and
- c) control means for controlling the precharge device to perform precharging the dynamic bus in a single phase of a clock cycle, and for controlling the writing device to perform writing of the data to the dynamic bus during the single phase of the clock cycle, said control means having a first input coupled to a clock signal line, a second input coupled to an output enable signal line, a first output coupled to said precharge device and a second output coupled to said writing device.
Dependencies are inferred from the claim text.